采用不同工艺制备了中波碲镉汞(HgCdTe)雪崩二极管(APD)器件, 利用不同方法对其结特性和增益随偏压变化关系进行了表征, 并基于Beck模型和肖克莱解析式进行了拟合分析.结果表明, 不同工艺制备的APD器件饱和耗尽区宽度分别为1.2 μm 和2.5 μm, 较宽的耗尽层有效抑制了高反偏下器件的隧道电流, 器件有效增益则从近100提高至1000以上.用肖克莱解析式拟合HgCdTe APD器件增益-偏压曲线, 获得了较好的效果.拟合结果与Sofradir公司的J. Rothman的报道相似.

The midium wave (MW) HgCdTe avalanche photodiodes (HgCdTe APDs) were prepared by two different processes. The pn junction characteristics and the relation between gain and bias voltage for HgCdTe APDs were characterized by two different methods. The gain-bias curves of APDs were fitted based on the Beck model and Shockley′s analytical expression. The results show that the widths of the saturated depletion region for APDs fabricated by two different processes are 1.2μm and 2.5μm respectively. The wide depletion region effectively suppresses the tunneling current at high reverse bias. The effective gain of the device increases from nearly 100 to over 1000. Shockley′s analytical expression gives an excellent fit to the gain-bias curves of HgCdTe APDs, and the fitting parameters are similar to the results of J. Rothman at Sofradir.